title: Effects of a fire response trait on diversification in replicated radiations.
abstract: Fire has been proposed as a factor explaining the exceptional plant species richness found in Mediterranean regions. A fire response trait that allows plants to cope with frequent fire by either reseeding or resprouting could differentially affect rates of species diversification. However, little is known about the generality of the effects of differing fire response on species evolution. We study this question in the Restionaceae, a family that radiated in Southern Africa and Australia. These radiations occurred independently and represent evolutionary replicates. We apply Bayesian approaches to estimate trait-specific diversification rates and patterns of climatic niche evolution. We also compare the climatic heterogeneity of South Africa and Australia. Reseeders diversify faster than resprouters in South Africa, but not in Australia. We show that climatic preferences evolve more rapidly in reseeder lineages than in resprouters and that the optima of these climatic preferences differ between the two strategies. We find that South Africa is more climatically heterogeneous than Australia, independent of the spatial scale we consider. We propose that rapid shifts between states of the fire response trait promote speciation by separating species ecologically, but this only happens when the landscape is sufficiently heterogeneous.
authors.affiliation: Department of Ecology and Evolution, Biophore, University of Lausanne, CH-1015 Lausanne, Switzerland; Swiss Institute of Bioinformatics, Quartier Sorge, CH-1015 Lausanne, Switzerland.
authors.forename: Glenn
authors.initials: G
authors.lastname: Litsios
authors.forename: Rafael O
authors.initials: RO
authors.lastname: Wüest
authors.forename: Anna
authors.initials: A
authors.lastname: Kostikova
authors.forename: Félix
authors.initials: F
authors.lastname: Forest
authors.forename: Christian
authors.initials: C
authors.lastname: Lexer
authors.forename: H Peter
authors.initials: HP
authors.lastname: Linder
authors.forename: Peter B
authors.initials: PB
authors.lastname: Pearman
authors.forename: Niklaus E
authors.initials: NE
authors.lastname: Zimmermann
authors.forename: Nicolas
authors.initials: N
authors.lastname: Salamin
mesh_terms: D001315:Australia; D002980:Climate; D019143:Evolution, Molecular; D029624:Ferns / Q000235:genetics*; D005390:Fires; D049810:Genetic Speciation; D014644:Genetic Variation; D019655:Quantitative Trait, Heritable; D012641:Selection, Genetic; D013019:South Africa
keywords: Climatic heterogeneity; Restionaceae; climatic preference evolution; mediterranean climate; speciation